This paper focuses on two types of electronics-based object detection systems for heavy truck applications: those sensing the presence of objects to the rear of the vehicle, and those sensing the presence of objects on the right side of the vehicle. The rearward sensing systems are intended to aid drivers when backing their vehicles, typically at very low “crawl” speeds. Six rear object detection systems that were commercially available at the time that this study was initiated were evaluated. The right side looking systems are intended primarily as supplements to side view mirror systems and as an aid for detecting the presence of adjacent vehicles when making lane changes or merging maneuvers. Four side systems, two commercially available systems and two prototypes, were evaluated.Three types of evaluation were performed for both the rear and right side object detection systems including hardware performance measurement, a human factors assessment of driver/system interfaces, and an assessment of driver subjective reactions to two systems. The hardware performance measurement consisted of determining the field of view of each system's sensors and, for the right side object detection systems only, determining the frequency of inappropriate alarms and missed vehicles while driving a combination-unit truck equipped with these systems on public roads. The evaluation of driver interfaces was performed using a human factors checklist that was developed specifically for this research and was based upon accepted human factors guidelines for the design of warnings. The last type of evaluation, which gathered subjective reactions to two systems, involved two focus group sessions conducted with drivers of a fleet of tractor-semitrailers that used one rear and one right side object detection system.An additional type of evaluation was performed which addressed the issue of human performance with side object detection systems. In this evaluation, subjects drove a test vehicle equipped with various right side object detection systems. This evaluation is described in the companion paper“Human Performance Evaluation of Heavy Truck Side Object Detection Systems,” *.The results of these tests and evaluations indicate that object detection system technology is still in the early stages of its development. Drivers of heavy trucks appreciate the value of these aids, but improvements in the technology are needed before the full potential of these systems for preventing crashes can be realized. Manufacturers should focus on improving system reliability and sensor performance and the human factors aspects of the control and display interface.